ZERO VALENT IRON NANOTECHNOLOGY

 Zero-valent iron nanoparticle technology is becoming an increasingly popular choice for treatment of hazardous and toxic wastes, and for remediation of contaminated sites. The diminutive size of the iron nanoparticles helps to foster effective subsurface dispersion whereas their large specific surface area corresponds to enhanced reactivity for rapid contaminant transformation. ZVI exhibit a typical core shell structure.The core consists primarily of zero valent or metallic iron while the mixed valent oxide shell is formed as a result of oxidation of the metallic iron. The applications of  ZVI have focused primarily on the electron donating properties. Under ambidant conditions it is fairly reactive in water and cancer as an excellent electron donor which makes it a versatile remediation material. 

In a PRB structure ground water flows passively through an engineered iron wall while contaminants are precipitated absorb or transformed in contact with the ZVI surface. Over the past decade extensive studies have demonstrated that ZVI nano particles are effective for the treatment of many pollutants commonly identified in groundwater include in perchloroethene and trichloroethene, carbon tetrachloride, nitrate, energetic munitions such as TNT and RDX ,legacy organohalogen pesticides such as Linden and DDT as well as heavy metals like chromium and lead.

The nanoparticle can be synthesized by two general strategies: top-down and bottom-up approaches. The former stocks with large size materials with the generation of nanoparticles by mechanical or chemical steps including milling, etching and machining. The latter approach entails the growth of nanostructures, atom by atom or molecule by molecule via chemical synthesis self-assembling, positional assembling and so on.

This is highly available and its synthesis is a very simple mechanism and thus it can be useful in waste water treatment plants.

Reference : Research paper of  Xiao - Qin Li, Daniel W. Elliott, and Wei - xian Zhang on Zero - Valent Iron nanoparticles for abatement of environmental pollutants : Materials and Engineering Aspects